<p>HOUMA — Law enforcement agencies have closed a portion of U.S. 90 in St. Mary Parish due to icy and slick conditions.</p><p>No road closures have been reported in Terrebonne or Lafourche parishes, but the highway between Calumet Bridge and Baldwin Bridge is closed, said State Police Master Trooper Bryan Zeringue.</p><p>Deputies said there have been more than 20 accidents in St. Mary Parish since this morning. The parish has also closed the courthouse for today and classes tomorrow.</p>